diff --git a/gomoku_rl/env.py b/gomoku_rl/env.py
index 0c5ce73..a79a5fa 100644
--- a/gomoku_rl/env.py
+++ b/gomoku_rl/env.py
@@ -27,7 +27,8 @@ def make_transition(
 ) -> TensorDict:
     # if a player wins at time t, its opponent cannot win immediately after reset
     reward: torch.Tensor = (
-        tensordict_t.get("win").float() - tensordict_t_plus_1.get("win").float()
+        tensordict_t.get("win").float() -
+        tensordict_t_plus_1.get("win").float()
     ).unsqueeze(-1)
     transition: TensorDict = tensordict_t_minus_1.select(
         "observation",
@@ -57,7 +58,8 @@ def __init__(
         board_size: int,
         device=None,
     ):
-        self.gomoku = Gomoku(num_envs=num_envs, board_size=board_size, device=device)
+        self.gomoku = Gomoku(
+            num_envs=num_envs, board_size=board_size, device=device)
 
         self.observation_spec = CompositeSpec(
             {
@@ -202,7 +204,8 @@ def _round(
         return_white_transitions: bool = True,
         is_last: bool = False,
     ) -> tuple[TensorDict | None, TensorDict | None, TensorDict, TensorDict]:
-        tensordict_t_plus_1 = self._step_and_maybe_reset(tensordict=tensordict_t)
+        tensordict_t_plus_1 = self._step_and_maybe_reset(
+            tensordict=tensordict_t)
 
         with set_interaction_type(type=InteractionType.RANDOM):
             tensordict_t_plus_1 = player_white(tensordict_t_plus_1)
@@ -249,7 +252,8 @@ def _round(
             )
             transition_black.set(
                 "invalid",
-                torch.zeros(self.num_envs, device=self.device, dtype=torch.bool),
+                torch.zeros(self.num_envs, device=self.device,
+                            dtype=torch.bool),
             )
         else:
             transition_black = None
@@ -466,6 +470,10 @@ def rollout_fixed_opponent(
         out_device=None,
         augment: bool = False,
     ) -> tuple[TensorDict, dict[str, float]]:
+        if not hasattr(self, "_t") and not hasattr(self, "_t_minus_1"):
+            self._t = None
+            self._t_minus_1 = None
+
         info: defaultdict[str, float] = defaultdict(float)
 
         tensordicts: list[TensorDict] = []
@@ -473,15 +481,19 @@ def rollout_fixed_opponent(
         start = time.perf_counter()
         info_buffer = defaultdict(float)
         self._post_step = get_log_func(info_buffer)
+
+        _tds, self._t_minus_1, self._t = self._rollout_fixed_opponent(
+            rounds=rounds,
+            player_black=player,
+            player_white=opponent,
+            return_black_transitions=True,
+            out_device=out_device,
+            augment=augment,
+            tensordict_t_minus_1=self._t_minus_1,
+            tensordict_t=self._t,
+        )
         tensordicts.extend(
-            self._rollout_fixed_opponent(
-                rounds=rounds,
-                player_black=player,
-                player_white=opponent,
-                return_black_transitions=True,
-                out_device=out_device,
-                augment=augment,
-            )
+            _tds
         )
 
         info.update(
@@ -493,16 +505,21 @@ def rollout_fixed_opponent(
         info_buffer.clear()
 
         self._post_step = get_log_func(info_buffer)
+        _tds, self._t_minus_1, self._t = self._rollout_fixed_opponent(
+            rounds=rounds,
+            player_black=opponent,
+            player_white=player,
+            return_black_transitions=False,
+            out_device=out_device,
+            augment=augment,
+            tensordict_t_minus_1=self._t_minus_1,
+            tensordict_t=self._t,
+        )
+
         tensordicts.extend(
-            self._rollout_fixed_opponent(
-                rounds=rounds,
-                player_black=opponent,
-                player_white=player,
-                return_black_transitions=False,
-                out_device=out_device,
-                augment=augment,
-            )
+            _tds
         )
+
         end = time.perf_counter()
         self._fps = (2 * rounds * 2 * self.num_envs) / (end - start)
         info.update(
diff --git a/tests/test_env.py b/tests/test_env.py
index 9d7918e..cc81006 100644
--- a/tests/test_env.py
+++ b/tests/test_env.py
@@ -47,7 +47,8 @@ def assert_layer_transition(
     same = (layer > EPS) & (next_layer > EPS)
     assert_tensor_1d_all((same == (layer > EPS)).all(-1).all(-1) | done)
     assert_tensor_1d_all(
-        (layer.long().sum(-1).sum(-1) + 1 == next_layer.long().sum(-1).sum(-1)) | done
+        (layer.long().sum(-1).sum(-1) + 1 ==
+         next_layer.long().sum(-1).sum(-1)) | done
     )
 
 
@@ -70,7 +71,8 @@ def assert_transition(tensordict: TensorDict, type: Type):
     layer1 = observation[:, 0]
     x = action // board_size
     y = action % board_size
-    assert_tensor_1d_all((layer1[torch.arange(num_envs, device=device), x, y] < EPS))
+    assert_tensor_1d_all(
+        (layer1[torch.arange(num_envs, device=device), x, y] < EPS))
     layer1 = layer1.clone()
     layer1[torch.arange(num_envs, device=device), x, y] = 1.0
     assert_tensor_1d_all(
@@ -78,17 +80,7 @@ def assert_transition(tensordict: TensorDict, type: Type):
     )
 
 
-def _debug_print(transition: TensorDict):
-    observation = transition["observation"]
-    next_observation = transition["next", "observation"]
-    done = transition["next", "done"]
-    print(observation)
-    print(next_observation)
-    print(done.item())
-    exit()
-
-
-def main():
+def test_rollout():
     device = "cuda:0"
     num_envs = 256
     board_size = 10
@@ -115,6 +107,15 @@ def main():
     ):
         assert_transition(transition, type=Type.black)
 
+
+def test_rollout_fixed_opponent():
+    device = "cuda:0"
+    num_envs = 256
+    board_size = 10
+    seed = 1234
+    set_seed(seed)
+    env = GomokuEnv(num_envs=num_envs, board_size=board_size, device=device)
+
     transitions, info = env.rollout_fixed_opponent(
         50,
         player=uniform_policy,
@@ -128,4 +129,5 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
+    # test_rollout()
+    test_rollout_fixed_opponent()